This invention relates to seat belt usage indicating systems, and more particularly to such a system that monitors the seat belt usage of occupants in rear seating rows and alerts the vehicle operator to the fact that a rear seat passenger is no longer securely belted.
Automotive vehicles generally include seat belt usage indicating systems for occupants of the front row seating positions of the vehicle. These systems are intended to provide a reminder to the front seat occupants if they fail to properly fasten their seat belts when the vehicle is in operation.
Since such a reminder is only appropriate and useful when a particular seat is actually occupied, most prior art systems use a seat occupancy sensor to determine the presence of an occupant in a particular seat. Such sensors typically comprise a pressure-sensing bladder or a load-responsive electrical switch installed within the seat. These prior art systems require special seat construction and wiring.
In view of the wide acceptance and use of seat belts, and the practice of many drivers to ensure that all passengers riding in the vehicle are properly buckled up before driving, it is very useful for the driver to know if a passenger""s seat belt becomes disconnected or disengaged during driving. The driver cannot easily monitor the seat belt use of passengers, especially rear seat passengers, during driving since his/her attention is properly directed to the act of driving.
In view of the above, it would be advantageous to provide a seat belt monitoring system that provides the vehicle operator with information as to the status of the seat belts in rear seating rows both prior to and during a trip.
An example of a seat belt usage indicating system appropriate for rear seats is disclosed in U.S. Pat. No. 5,483,221. In this patent, a system monitors the seat belts in a motor vehicle and a reminder is initiated in response to a belt buckle sensor indicating an engaged or non-engaged state of the buckle. A vehicle sensor indicates when the vehicle is in use, and an annunciator produces an audible reminder if any belt that was initially engaged becomes disengaged. Thus, monitoring of the continued buckling of a seat belt is provided without need for seat occupancy sensors. The system, however, does not allow for continued monitoring of seat belt use if seat occupancy changes because of passengers being dropped off, picked up, or changing seats. Also, the system does not provide any indication to the vehicle operator how many passengers are properly buckled at the start of a trip.
The present invention monitors the secured/unsecured status of seat belts in rear seating rows in a manner not requiring seat occupancy sensors, and allows the rear seat passengers to temporarily unfasten their seat belt as necessary to move from one seating position to another without continuous alerting of the vehicle operator. The invention also allows continued monitoring of rear seat passengers after the number of belted passengers changes due to the dropping off and/or picking up of passengers.
These and other advantages are achieved by the monitoring and alerting system comprising a plurality of seat belt sensors for producing belt status signals indicating the secured/unsecured condition of each seat belt in the rear seating rows, a display for producing a visible indication of the status of at least one of the seat belts, and a control module coupled to the seat belt sensors to receive the belt status signals and coupled to the display. The control module causes the display to indicate an initial number of the rear seat belts in the secured condition at a base time, causes the display to provide a visible alert message to indicate if the number of belts in the secured condition falls below the initial number after the base time, and terminates the alert message if the number of belts in the secured condition returns to the initial number.
In a preferred embodiment of the invention, the system further comprises an annunciator for producing an audible alerting signal. In a further preferred embodiment of the invention, the secured/unsecured condition is determined by monitoring a retractor reel of the seat belt, the secured condition being defined by the seat belt being paid out beyond a threshold length and the unsecured condition being defined by the seat belt being retracted shorter than the threshold length.
In a further preferred embodiment of the invention, the base time is established by a vehicle in-use signal that indicates one or more of the following conditions: when electrical power is applied to vehicle electrical systems, when the vehicle has reached a predetermined speed, and/or when one or more of the vehicle doors is closed.
In a further aspect of the invention, the visible display is provided by a vehicle message center providing information as to which of the rear row seating positions are initially in the secured condition, and which of the initially secured positions transition to the unsecured condition.
The present invention also comprises a method of a monitoring the status of seat belts in a rear seating row.